London officials will have to remove a 143-ton "fatberg" from a London sewer after it caused blockages in a Victorian-era tunnel.

A fatberg is made up of congealed household waste such as cooking oil, diapers, and wet wipes that bind together into a blob. Smaller fatbergs commonly block household sewer pipes, but it is unusual to see one weighing as much as 11 double-decker buses and as long as more than two (American) football fields.

Thames Water said it would take three weeks to remove the 820-foot fatberg, the BBC reported. Workers have already begin using high pressure hoses to break up the clog, suck up the pieces into tankers, and transport it to a recycling site in Stratford.

“It’s basically like trying to break up concrete,” Thames Water's head of waste networks Matt Rimmer said, the BBC reported. “It’s frustrating as these situations are totally avoidable ... the sewers are not an abyss for household rubbish.”

A waste oil collection point has now been set up for businesses to recycle their used cooking oil, the BBC reported.

Other fatbergs have blocked sewers in and near London in 2013 and 2015.

Twitter users imagined what all that fat was doing to people’s arteries and what it looked like.